package controller;

import com.fasterxml.jackson.databind.ObjectMapper;
import model.User;
import model.UserDao;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;
import java.io.IOException;

/**
 * \* Created with IntelliJ IDEA.
 * \* User: Administrator
 * \* Date: 2022/6/12
 * \* Time: 10:58
 * \* To change this template use File | Settings | File Templates.
 * \* Description:
 * \
 */
@WebServlet("/login")
public class LoginServlet extends HttpServlet {
    private ObjectMapper objectMapper = new ObjectMapper();
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("utf8");
        resp.setContentType("utf8");
        //1.获取到请求中的参数
        String username = req.getParameter("username");
        String password = req.getParameter("password");
        if(username == null || "".equals(username) || password == null ||"".equals(password)){
            //请求的内容缺失，肯定是登录失败
            resp.setContentType("text/html;charset=utf8");
            resp.getWriter().write("当前的用户名或密码为空");
            return;
        }
        //2.和数据库中的内容进行比较，
        UserDao userDao = new UserDao();
        User user = userDao.selectByName(username);
        if(user == null || !user.getPassword().equals(password)){
            //用户没查到或者密码不匹配，也是登录失败
            resp.setContentType("text/html;charset = utf8");
            resp.getWriter().write("用户名或密码错误！");
            return;
        }
        //3.如果比较通过，就创建会话，
        HttpSession session = req.getSession(true);
        //把刚才的用户信息存储到会话中
        session.setAttribute("user",user);

        //4.返回一个重定向报文，跳转到博客列表页
        resp.sendRedirect("blog_list.html");
    }

    //这个方法用来让前端检测当前的登录状态

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("application/json;charset=utf8");
        HttpSession session = req.getSession(false);
        if(session==null){
            //检测下会话是否存在，不存在说明未登录
            User user = new User();
            resp.getWriter().write(objectMapper.writeValueAsString(user));
            return;
        }
        User user = (User) session.getAttribute("user");
        if(user == null){
            //虽然有会话，但是会话没有user对象，也视为未登录
            user = new User();
            resp.getWriter().write(objectMapper.writeValueAsString(user));
            return;
        }
        //已经登录的状态
        //注意，此处不要把密码返回到前端
        user.setPassword("");
        resp.getWriter().write(objectMapper.writeValueAsString(user));
    }
}
